Ordinarily, a board work machine is provided with a conveyance device for conveying a circuit board, and the conveyance device has a conveyor belt. Then, the circuit board is placed on the conveyor belt, and the circuit board is conveyed toward the downstream side by the conveyor belt being rotated. As described in the patent literature below, a protruding section is formed on a placement face of a circuit board on a conveyor belt, and the circuit board is reliably pushed out toward the downstream side by the protruding section.    PTL 1: JP-A-05-039124